A conventional image forming apparatus includes a charger having a discharge wire and a grid, i.e. a scorotron charger. In order to detect an abnormal discharge, the image forming apparatus has a discharge detection circuit connected to the grid. The discharge detection circuit detects an abnormal discharge (a spark discharge) occurred in the scorotron charger due to dust on the wire etc.
The discharge detection circuit can suitably detect the abnormal discharge caused between the discharge wire and the grid of the charger. However, because the charge voltage is high (e.g. ranging from 6 kV to 8 kV), an abnormal discharge may occur also in a charge voltage path to the charger.
Therefore, there is a need for an image forming apparatus that can detect: an abnormal discharge in a charger thereof; and, furthermore, an abnormal discharge due to the charge voltage in a charge voltage path to the charger.